Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
  • F16L15/00—Screw-threaded joints; Forms of screw-threads for such joints
  • F16L15/08—Screw-threaded joints; Forms of screw-threads for such joints with supplementary elements
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49826—Assembling or joining
  • Y10T29/4984—Retaining clearance for motion between assembled parts
  • Y10T29/49845—Retaining clearance for motion between assembled parts by deforming interlock
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T29/00—Metal working
  • Y10T29/49—Method of mechanical manufacture
  • Y10T29/49826—Assembling or joining
  • Y10T29/49877—Assembling or joining of flexible wall, expansible chamber devices [e.g., bellows]

Definitions

• the present invention relates to improved threaded spacers for use in joining adjacent sections of drill pipe in a drill string for recovering oil or gas from a subterranean formation, as well as an improved method for maldng such threaded spacers.
• the threads of the pipe are typically coated with a suitable thread compound.
• These compounds usually contain finely divided metal powder such as zinc or lead and sometimes other ingredients such as active sulfur.
• these compounds may degrade over time, or under the influence of the extreme conditions encountered in use, leading to loss of their anti-galling properties. Firrthe ⁇ nore, many of these compounds are now classified as hazardous substances because of their high metal particle content.
• the threaded spacer of Italian Patent 980421 is described as being made from copper/beryllium alloy.
• This alloy has a unique combination of properties, including wear and galling resistance, when mated with steel and other metals. It is therefore claimed that this device can totally replace conventional thread compounds, thereby eliminating the environmental and performance problems associated with these compounds.
• Italian patent 980421 appears to be a conceptual disclosure only. No method of manufacture is disclosed. Nor is the description of wall thicknesses clear.
• the present invention in one embodiment provides a novel process for making a thin walled threaded spacer for use in joining adjacent sections of drill pipe, the spacer having a hollow conical section and an integral spacer flange, the wall thickness of the hollow conical section being about 0.5 mm or less with the spacer flange being about 5 to 40 times as thick as the conical section wall thickness, the spacer conical section defining cooperating helical threads for mating with the threads of adjacent sections of drill pipe, wherein the process comprises mechanically deforming a strip of metal to form a preform defining a preform conical section and an integral preform flange in a first process step and then further mechanically deforming the spacer conical section to impart helical threads on its inside and outside faces, thereby forming the desired threaded spacer product.
• Fig. 1 is a schematic cross sectional view of the threaded spacer of Italian Patent 980421 being inserted between the threads of two joined sections of drill pipe in a drill string;
• Fig. 2 is an enlarged cross sectional view of the portion of the threaded spacer of Fig. 1 within circle A;
• Fig. 3 is a view similar to Fig. 2 illustrating an alternate embodiment of the threaded spacer of Italian Patent 980421;
• Fig. 4 is a schematic cross sectional view of the threaded spacer of the present invention.
• Fig. 5 is an enlarged cross sectional view of the portion of the threaded spacer of Fig. 4 within circle B;
• Fig. 6 is a schematic cross sectional view illustrating the inventive process for making the inventive threaded spacer of Fig. 4;
• Figs. 7, 8 and 9 are cross sectional views similar to Figs. 1 to 5 illustrating an alternate embodiment of the invention. DETAILED DESCRIPTION
• Fig. 1 illustrates the threaded spacer 20 of Italian Patent No. 980421 shown being inserted between the threads of two joined sections of drill pipe 22 and 24 in a drill string.
• Drill pipe section 22 includes a male or "pin" portion 26 defining a conical face 28 which, in turn, defines a helical thread/groove 30 therein.
• drill pipe section 24 includes a female or "box” portion 36 defining helical thread/groove 32 therein intended to mate with helical thread/groove 30 of drill pipe section 22.
• Drill pipe section 22 defines a shoulder 38 which is adapted to face and mate with shoulder 40 of drill pipe section 24.
• Threaded spacer 20 includes a truncated conical section 42 which is received between cooperating helical thread/grooves 30 and 32 in drill pipe sections 22 and 24 and a flange 44 received between shoulders 38 and 40 of the drill pipe sections.
• truncated conical section 42 of threaded spacer 20 can be received between mating helical thread/grooves 30 and 32 of drill pipe sections 22 and 24, respectively, the wall forming truncated conical section 42 is actually undulating in cross-section.
• Figs. 2 and 3 are reproductions of two figures in the Italian patent showing detailed views of the portion of truncated conical section 42 within circle A of Fig. 1. Two different embodiments with different wall thicknesses are illustrated in Figs. 2 and 3.
• Italian Patent 980,421 is vague with respect to the wall thickness of truncated conical section 42. There is some indication, however, that this thickness may be about 1 to 2 mm.
• the groove depth of typical drill pipe having outside diameters of 6 to 8 inches is on the order of 3 to 5 mm.
• Figs. 2 and 3 herein, which essentially reproduce figures in the Italian patent, show that the wall thicknesses, L and Q, are roughly 1/3 to 2/3 as thick as the groove depth R. This translates to wall thicknesses L and Q that can range on the order from about 1 to 3 mm.
• a novel threaded spacer of the type illustrated in Italian Patent 980421 is made by a new process in which a metal strip is mechanically deformed to form a preform and the preform then further mechanically deformed to impart appropriate grooving thereto.
• the novel thin walled threaded spacer produced by this process is illustrated in Figs. 4 and 5 generally at 50. It is composed of a hollow, truncated, conical section 52 formed by conical wall 54 defining an inside face 56 and an outside face 58. A smaller open end 60 is defined on one side of conical section 52, while a larger open end 62 is defined on the opposite end of conical section 52. Integral with conical wall 54 on the larger end of conical section 52 is flange 64, which is arranged in a plane perpendicular to the axis 66 of conical section 52.
• the inside face 56 and outside face 58 of conical wall 54 define cooperating grooves 68 and 70, respectively, for receiving mating threads of adjacent sections of drill pipe to be joined.
• the wall thickness of the portion of conical wall 54 defining grooves 68 and 70 is thin enough so that this conical wall is actually undulating in cross section, as shown in both Figs. 4 and 5.
• the thickness of conical wall 54 is considerably thinner, typically on the order of 0.5 mm or less, preferably 0.4 mm or less, more preferably about 0.3 mm or less.
• the thickness of the portion of conical wall 54 defining grooves 68 and 70 is typically about 20% or less, preferably about 10% or less, even 5% or less, than the depth of grooves 68 and 70, shown as distance D in Fig. 5.
• Flange 64 of the inventive threaded spacer can be any thickness necessary to fill, substantially completely, the annular space formed between the shoulders of adjacent drill pipe sections when joined together with the inventive threaded spacer. See Fig. 1. This depends on a number of factors including the shoulder design of the drill pipe, the angle of conical wall 54 with respect to axis 66 and the thickness of conical wall 54. i general, flange 64 will be about 5 to 40, preferably 15 to 30, more preferably 20 to 25, times as thick as the wall thickness of conical wall 54.
• conical wall 54 has a wall thickness of about 0.012 inches (about 0.3 mm), which represents about 9% of the depth of grooves 68 and 70.
• flange 64 in the particular embodiment shown is about 0.30 inches (about 7.2 mm) thick, or about 25 times as thick as the wall thickness of conical wall 54.
• the inventive threaded spacer has a thin wall in its conical section in order to avoid development of damaging stress levels in the drill pipe thread. This means that the conical section need only be thick enough to remain physically intact during joining and use of the drill pipe for recovery or oil or gas.
• Certain specific alloys exhibit a unique combination of properties, including high electrical conductivity, high strength, corrosion resistance, fo ⁇ nability, low coefficient of sliding friction and resistance to wear and resistance to galling when mated with steel or other ferrous or non-ferrous metal. These alloys make ideal candidates for making the inventive threaded spacer, since they not only provide the desired lubricating and anti-galling effects on a long life basis but also are relatively easy to form into thin shapes by mechanical or electromechanical deformation without machining.
• Such alloys are copper/beryllium alloys containing at least about 0.1 wt. % to 10 wt.% or more beryllium, preferably at about 0.75 to 5 wt.% beryllium, more preferably about 1.25 to 3 wt.% beryllium.
• a most preferred copper/beryllium alloy contains about 2 to 2.5 weight percent beryllium.
• Such alloys can contain other additional ingredients which do not fundamentally alter their basic properties. Examples are Ni, Co, Zr, Ti, Hf, Sn, Pb, Ag, Mg, Si, Al and Cr.
• Exemplary alloys are described, for example, in US 5,993,574, US 4,179,314, US 4,551,187 and US 4,657,601, the disclosures of which are incorporated herein by reference.
• the particular threaded spacer illustrated in Fig. 4 and 6 is made from copper/beryllium alloy containing 2 weight % of beryllium.
• Other alloys useful in making the inventive threaded spacer by means of the inventive process are those composed predominantly of Cu, Ni or Al alloyed with one or more of Sn, Zn, Zr, Pb, Ti, Si, Al, Cr, Mg, Ni, Cu, hi and Bi.
• the inventive threaded spacer can be made from less expensive materials as well, although useful life, anti-galling effect and/or ease of formation may be adversely affected.
• the inventive threaded spacer is made by a process based mechanical deformation of a metal strip.
• strip is meant any sheet or strip of metal having an essentially uniform thickness over an area many times longer and wider than its thickness. A strip is therefore distinguished from a rod, bar or ingot, whose length and/or width may be similar to its thickness.
• mechanical deformation is meant a process in which the shape is imparted to a workpiece by the application of mechanical force without removal of material from the workpiece by machining or other cutting operation.
• Many different mechanical deformation processes are known and can be used in the inventive process. Examples are cold forming, deep drawing, wall ironing, spin forming, thread rolling, semi-molten forming, hydroforming, warm forging, hot forging, cold forging, magneforming, thixoforging and explosive forming.
• Preferred mechanical deformation processes for use in the inventive process are magneforming and thixoforging.
• a preform is produced from a metal strip by mechanical deformation.
• this preform will have a size and shape approaching the gross size and shape of the ultimate threaded spacer product to be produced including a flange and truncated conical section, but without grooving in the comcal section.
• This step is most conveniently done by forming a metal strip over a conical die or form similar in shape, but slightly smaller in outside dimension than, conical wall 54 of the product threaded spacer.
• Forming the truncated tip of the preform can be accomplished either as part of the formation step or by forming a closed-ended conical tip first and then removing the tip to achieve a truncated end.
• the metal strip used in making the preform will preferably have a thickness at least equal to, and preferably larger than, the thickness of flange 64 of the ultimate threaded spacer product in order to simplify formation of flange 64.
• the inventive threaded spacer be formed from a single, unitary piece of starting material, and therefore the metal strip should be thick enough to allow all of the necessary metal working operations to be done without the need for adding additional material thereto.
• grooves 68 and 70 are formed in the preform conical section.
• This can be done by any known mechanical deformation technique which will impart grooves 68 and 70, and hence the undulating wall structure illustrated in Fig. 5., to the truncated conical section of the preform.
• suitable mechanical deformation techniques for this step are wall ironing, spin forming, thread rolling, die forging, hydroforming, magneforming and thixoforging. Especially preferred are magneforming and thixoforging.
• Fig. 6 illustrates a preferred embodiment of the inventive process in which the second step of the inventive process is accomplished by vacuum magneforming.
• preform 72 is placed within a die 74 having a grooved surface 76 whose grooves correspond to the size and shape of grooves 68 and 70 to be formed in conical wall 54 of the product threaded spacer.
• Die 74 is housed in container 78, which is adapted to be closed to the atmosphere.
• a vacuum system (not shown) is connected to container 78, so that the container interior can be evacuated to a convenient vacuum on the order of 3 x 10 3 to 7 x 10 3 , preferably 4 x 10 3 to 5 x 10 3 , Torr. Although this vacuum is unnecessary, it is helpful in improving the definition of the grooves by removing air that may be trapped during the maneforming step.
• a coil 80 connected to a source capable of generating a large electrical pulse (not shown), is provided in the hollow portion inside the truncated conical section of preform 72.
• the inventive threaded spacer is formed from separate parts which are joined together preferably in the second mechanical deformation step and which may thereafter also be additionally joined together by spot welding at various locations around the surface of its annular flange.
• a preform section 172 is made in a similar manner as preform 72 of Fig.
• annular flange 164 has the same wall thickness as the remainder of the preform.
• annular flange 164 is larger radially than flange 64 of the previously described embodiment, with the outer end of this flange being bent downwardly by 90° to form vertical extension 180.
• Annular ring 182 is inserted in the hollow formed between extension 180, flange 164 and the wall of the preform, as illustrated in Fig. 7, and securely fixed in place by bending the outer (lower) end of extension 180 around the annular ring in the manner illustrated in Fig. 9.
• s spot weld zone may be used to join the preform and the annular ring. The advantage of this approach is that it eliminates the stretching, drawing or like mechanical working step needed to reduce the thickness of the preform conical wall in the previous embodiment.
• threaded spacers for drill pipe are made by a forming process using metal strip as the starting material and using mechanical deformation working techniques for the forming steps.
• threaded spacers can be made using less expensive metal forming techniques to produce product spacers significantly thinner than contemplated in the past.
• threaded spacers based on expensive alloys such as copper/beryllium or Cu/Ni/Sn can be made at significantly lower cost than possible by the approaches previously suggested.
• this allows use of threaded spacers as suggested in Italian Patent 980421 to be transformed from an impractical, theoretical idea to practical reality.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Earth Drilling (AREA)
• Forging (AREA)
• Dowels (AREA)
• Polishing Bodies And Polishing Tools (AREA)
• Metal Extraction Processes (AREA)
• Prostheses (AREA)
• Materials For Medical Uses (AREA)

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Citations (7)

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• 2000
  • 2000-03-09 US US09/522,134 patent/US6371224B1/en not_active Expired - Lifetime
• 2001
  • 2001-03-07 WO PCT/US2001/007278 patent/WO2001066903A1/fr active IP Right Grant
  • 2001-03-07 DK DK01916453T patent/DK1264068T3/da active
  • 2001-03-07 CN CNB018090281A patent/CN1273718C/zh not_active Expired - Fee Related
  • 2001-03-07 AT AT01916453T patent/ATE350562T1/de not_active IP Right Cessation
  • 2001-03-07 AU AU2001243479A patent/AU2001243479B2/en not_active Ceased
  • 2001-03-07 MX MXPA02008815A patent/MXPA02008815A/es active IP Right Grant
  • 2001-03-07 RU RU2002126259/03A patent/RU2259459C2/ru not_active IP Right Cessation
  • 2001-03-07 DE DE60125730T patent/DE60125730T2/de not_active Expired - Fee Related
  • 2001-03-07 EP EP01916453A patent/EP1264068B1/fr not_active Expired - Lifetime
  • 2001-03-07 AU AU4347901A patent/AU4347901A/xx active Pending
  • 2001-03-07 CA CA002402479A patent/CA2402479C/fr not_active Expired - Fee Related
  • 2001-03-07 BR BRPI0109181-6A patent/BR0109181B1/pt not_active IP Right Cessation
  • 2001-04-30 TW TW090105570A patent/TW479103B/zh not_active IP Right Cessation

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